The IPCC has finalized the First-Order Draft of its 2027 Methodology Report on Carbon Dioxide Removal Technologies, Carbon Capture, Utilization, and Storage — and the expert review window runs just seven weeks, from November 2 to December 20, 2026. Reviewer registration closes December 11.

That is the clock. For anyone working in CO2 capture, transport, geological storage, or carbon removal accounting, these dates mark the one formal opportunity to shape the draft before it hardens into the global accounting rulebook for carbon management under national greenhouse gas inventories.

More than 100 lead authors and international contributors produced the draft. Its scope covers accounting frameworks for:

• Point-source CO2 capture
• CO2 transport networks
• Sub-seabed and onshore geological storage
• Carbon utilization
• Durable biogenic and synthetic carbon dioxide removal (CDR) pathways

In plain terms: this document decides how tonnes of captured, stored and removed CO2 get counted, reported and verified in national GHG inventories.

Why does a methodology report matter to the material stream?

Because measurement rules are market infrastructure. Once national inventories carry standardized CDR and CCUS accounting, projects gain a common basis for claims, and reporting becomes comparable across jurisdictions. The IPCC frames the draft as a foundational step toward exactly that — standardized global accounting rules for carbon management technologies.

The panel is not soliciting opinions on whether carbon removal is good policy. It wants technical feedback from people who work the details: researchers, engineers, and inventory practitioners specializing in CO2 transport logistics, geological storage integrity, direct air capture (DAC), and carbon accounting methodologies.

The review process, the IPCC notes, is the core mechanism that keeps its technical guidance scientifically rigorous, policy-neutral, and directly usable by national inventory compilers. Takeaway: the rulebook's rigor depends on who shows up to review it.

What happens after December 20?

The expert review is not the final gate. After it closes, the report moves to a secondary joint review by governments and experts together. Only then does it go to IPCC member nations for final approval, ahead of its scheduled adoption into national climate reporting frameworks.

So the sequence is:

1. Expert Review: November 2 – December 20, 2026
2. Joint government-expert review
3. Final approval by IPCC member nations
4. Adoption into national reporting frameworks, targeted for 2027

Each stage can reshape the accounting treatment of capture, transport, storage, utilization and durable removals. Comments filed in the first window carry the most leverage, because they land before governments weigh in.

Takeaway: the earlier the comment, the cheaper it is to move the number.

Who should register — and by when?

Registration is open now. The cutoff is December 11, 2026, nine days before the review window itself closes on December 20.

The IPCC is explicitly targeting specialists in:

• CO2 capture engineering
• CO2 transport logistics
• Geological and sub-seabed storage integrity
• Direct air capture
• Carbon accounting methodology

This is a technical peer-review process, not a public consultation. Its output feeds the accounting backbone that project developers, storage operators and inventory agencies will work under once the report is adopted.

Takeaway: if your operation moves CO2, this is the rulebook you will report against — and the comment window is open now.

The milestone to watch next is the close of the Expert Review on December 20, 2026 — what survives that gate goes to governments, and then to the 2027 adoption that fixes how carbon management counts.